A typical toilet used in domestic applications may include a toilet bowl mounted on a floor surface. The toilet bowl may be in communication with a drain that takes away the contents of the toilet bowl. The toilet may also include a water supply tank at a higher elevation that provides the proper amount of water during a flush cycle of the toilet bowl. In order to refill the tank after a flush cycle, a float in the toilet tank lowers, thereby opening a fill valve that supplies replacement water to the tank. The float may respond to the rising level of the liquid in the tank by closing the fill valve. If the drain opening of the toilet is clogged and the toilet is flushed, the fresh replacement water coming from the toilet tank to the bowl may cause the water level in the toilet bowl to rise. This may create a hazard of an overflow of the contents in the toilet bowl.